Compositions for treating fibrous substrates to enhance the water-repellency of the substrates are known and described in the literature, for example, in “Fluorinated Surfactants and Repellents,” E. Kissa, Surfactant Science Series, vol. 97, Marcel Dekker, New York, Chapter 12, p. 516-551, or in “Chemistry and Technology of Silicones,” by W. Noll, Academic Press, New York, Chapter 10, p. 585-595; however, there is a continual need for compositions that provide high water repellency, in particular high initial water repellency, and in certain situations, high water-repellent durability, especially compositions that are fluorine-free.